Use
"content": {
"description": "Parsed record content, e.g. MARC record"
}
instead of
"content": {
"description": "Parsed record content, e.g. MARC record",
"type": "string"
}

Also a marshaller and unmarshaller must be changed to encode and decode parsedRecord entity.

• during marshalling content must be represented as an general JsonObject

• during unmarshalling content must be represented by io.vertx.core.json.JsonObject